Showing papers in "Transition Metal Chemistry in 1979"

Structural studies on isoxazole derivatives: The crystal and molecular structures of Tetra(3-amino-5-methylisoxazole)bis(isothiocyanate)-nickel(II) and Tetra(3-amino-5-methylisoxazole)bromocopper(II) bromide

Abstract: The structures of the title compounds were both solved from diffractometer data by direct methods and refined by full-matrix least-squares toR=463% for 3069 independent reflections for the nickel compound [triclinic,a=10499(7),b=13295(8),c=10182(7) A, α=9213(8), β=10358(7), γ=6879(7)°;Z=2 Space group P1] and toR=798% for 772 independent reflections for the copper compound [tetragonal,a=12939(6),c=14991(7) A;Z=4 Space group P4/ncc] In the first compound two chemically equivalent, crystallographically independent molecules are present, in which each nickel atom attains an octahedral coordination involving four N(ring)-bonded isoxazole molecules and two isothiocyanate groups In the copper compound, the metal atom shows square-pyramidal fivecoordination with the four symmetry-related organic molecules bondedvia N(ring) in the square plane and one bromide ion (the other is not coordinated) in the apical position

π-Arene complexes of the group VIII transition metals

Abstract: Synthetic methods, structural and chemical aspects of Group VIII η6-arene complexes have been reviewed. A section on metal vapor syntheses of these π-arene complexes -has been included. π-Arene complexes of Group VIII metals in all oxidation states (0, +1, +2, +3) are discussed. Particular emphasis on the π-arene ligands lability has been made, and the resultant rich chemistry of the complexes outlined, including catalytic properties.

Mineral formation from aqueous solution. Part I. The deposition of hydrozincite, Zn5(OH)6(CO3)2, from natural waters

Abstract: Naturally occurring waters in the oxidized zone of a Pb-Zn orebody have been collected where they are responsible for the formation of solid hydrozincite, Zn5(OH)6(CO3)2. The solutions were analysed and the computer programme COMICS used to describe the complex ion distribution in each case. From the results, the solubility product for hydrozincite has been recalculated as log KSP=−14.9(0.1). This value has been used to calculate the fields of stability of some secondary zinc minerals and illustrates the reason for the apparently anomalous stability of hydrozincite in nature, compared with what might be expected from considerations of earlier data.

The preparation, crystal and molecular structure of [MoCl2(NH)O(EtPh2PO)2] the preparation, crystal and molecular structure of [MoCl2(NH)O(EtPh2PO)2]. An example of terminal, nonlinear-imido-coordination

Abstract: Reaction of MoOCl3 with Me3SiN3 m THF followed by addition of tertiary phosphine oxides, RPO3(R3=Ph3, Ph2Et, Ph2Me), gives [MoCl2(NH)O(OPR3)2]. The crystal and molecular structure of the compound has been determined by x-ray diffraction methods. The complex crystallises in the monoclinic space group P21 /a with four molecules in a unit cell having dimensions a=15.667(8) A, b=20.135(9) A, c=9.726(7) A and β=95.01(1) A. A total of 3510 reflections were collected by counter techniques using MoKα radiation. The structure was refined on 2597 reflections with I > 2.58 σ (I) by full matrix least squares, using anisotropic temperature factors for all nonhydrogen atoms, to give a final R factor of 0.082. The overall configuration of the distorted octahedral complex istrans-dichloro-cis-bis[ethyl(diphenyl)phosphineoxide]cis-(oxo) imido with the molybdenum formally in the oxidation state (VI). The imido hydrogen has been located, and the Mo-N-H system is nonlinear.

New dioxouranium(VI) complexes with tridentate dibasic Schiff bases containing ONO donor sets

Abstract: Several new dioxouranium(VI) complexes with the tridentate dibasic Schiff bases derived from salicylaldehyde, 5-chloro-, 5-bromo-, 5-nitro-, 3,5-dichloro-, 4-methoxy-, 5-methoxy- and 3-ethoxysalicylaldehyde and 2-hydroxy-1-naphthaldehyde ando-aminobenzyl alcohol, have been synthesized from uranyl acetate dihydrate and the Schiff base in methanol The complexes are of the type UO2(AAA) MeOH (where AAAH2 = a tridentate dibasic Schiff base) The complexes have been characterized by elemental analyses, ir and electronic spectra, conductance, magnetic susceptibility and molecular weight measurements Thev (U=O) stretching frequency of the complexes occurs atca 900 cm−1 and the U-O distance is 174A The complexes are monomers, diamagnetic and octahedral

The crystal and molecular structure of chlorobis(N-ethyl-1 3-imidazolidine-2-thione)copper(I)

Abstract: The crystal structure of the title compound has been determined from x-ray diffractometer data by the heavy-atom method and refined anisotropically by least-squares calculations. Crystals are monoclinic, space groupP 21/c, with unit cell dimensions:a=7.321(1),b=14.622(2),c=14.827(2) A,β=92.95(2)∘, Z=4. The finalR index is 4.6%. The copper coordination is trigonal, involving the sulphur atoms of twoN-ethyl-1,3-imidazolidine-2-thione molecules and one chlorine atom. The structure is held together by two intramolecular N-H⋯Cl hydrogen bonds and by normal van der Waals interactions.

Novel five- and six-coordinate zinc (II), cadmium (II) and mercury(II) complexes of macrocyclic ligands

Abstract: Complexes of 2,6-dipicolinic acid hydrazide, DPH, with ZnII, CdII and HgII have been prepared and characterized by elemental analysis, i.r. and electronic spectra and by electrical conductance measurements. The ligand is terdentate, having coordination sites at two deprotonated amide-nitrogen and pyridine-nitrogen atoms. The ZnII and HgII complexes are pentacoordinate whereas the CdII complexes are hexacoordinate and have trigonal bipyramidal and pseudooctahedral stereochemistries, respectively. The Zn, Cd and Hg ions induce cyclization of DPH complexes upon reaction withβ-diketones. The complexes of macrocyclic ligands so formed have the same stereochemistries as those of DPH.

Pentane-2,4-dione complexes of technetium99

Abstract: Pentane-2,4-dionatotechnetium99 complexes of the type PPh4[TcX4(acac)], TcBr3(acac)PPh3, TcX2(acac)2, TcX2 (acac) (PPh3)2, TcX(acac)2 PPh3 and Tc(acac)3 (X=Cl or Br) have been prepared and characterized. Where possible, their configurations have been determined from elemental analyses, conductivity and magnetic susceptibility measurements, and by i.r. and u.v.-visible spectroscopy.

Synthesis and catalytic activity of some cationic complexes of rhodium(I) with norbornadiene and group Vb ligands

Abstract: The syntheses of [Rh(NBD)L2 ]ClO4 complexes (L=nitrogen donor ligand), obtained from [Rh(NBD)2]ClO4, and their reactions with triphenylphosphine and carbon monoxide are described.

Thermodynamics of 2,2′,2′'-terpyridinecopper(II) complexes in aqueous solution

Abstract: The thermodynamic quantities relative to the protonation and the complexation of 2,2′,2′'-terpyridine with copper(II) ion have been determined at 25° and I=0.1 mol dm−3 (NaNO3). The ΔG∘ data was obtained by potentiometric measurements; a copper selective electrode was employed for the study of the complexation equilibria. The ΔH∘ values have been determined by direct calorimetry. The hydrolytic species, existing at pH>6 and their relative ΔG∘ and ΔH∘ values have also been obtained. From the thermodynamic data the importance of enthalpy and entropy terms in stabilizing the complexes is assessed. Moreover some considerations on the chelating effect are reported.

The C, N-Bonding of the N-Ethylethyleneimine (EtNCHMe) Ligand to Niobium, Tantalum and Tungsten

Abstract: The r ecen t r e p o r t by Takahash i et al. (1) t h a t the novel o rganometa l l i c e t h y l i m i n o ( C , N ) t r i s ( d i e t h y l a m i d o ) t a n t a l u m c o m p o u n d ( la ) is f o r m e d as an i n t e r m e d i a t e in the t h e r m a l d e c o m p o s i t i o n of Ya(NEt2)5 [which u l t i m a t e l y gives Ta (NEt ) (NEt2 )3] (2) p r o m p t s us to disclose comparab l e obse rva t ions in t he d i e t h y l a m i d o chemis t ry of n i o b i u m and tungs ten . Earl ier work(3) es tab l i shed t h a t r eac t ion of NbCls (1 tool) and LiNEt 2 (5 mols) gave main ly the pa ramagne t i c Nb(NEt2 )a in con t r a s t to the TaC15 reac t ion (2). Nevertheless , s u b s e q u e n t n.m.r , work revealed t h a t some Nb v species are present wi th the Nb(NEt2 )4 even af te r dis t i l la t ion. Work on the separa t ion and cha rac te r i za t ion of these c o m p o u n d s is still in progress bu t t he c o m p l e x 1H n.m.r , s p e c t r u m (100 MHz in C6D 6 ) shows clearly t h a t b o t h e thy l imino ( C , N ) t r i s ( d i e t h y t a m i d o ) n i o b i u m ( l b ) [CH3-doub le t 1.776 and CH-quar t e t 2 .476, J = 5.0 Hz, for the CH3--CH--N m o i e t y and two doub le qua r t e t s in 1 : 6 rat io, 3.856 unresolved and 3.44, 3 .416, J = 7.0 Hz for the prochi ra l CHz-groups in EtNand Et2N-groups, and co r re spond ing t r ip le ts in 1 : 6 rat io, 1.456 and 1.046, J = 7.0 Hz for t he m e t h y l groups] and p r o b a b l y N b( N E t ) ( N E t 2 ) a [ incomple t e ly resolved CH 2-quar te t s in the 3.86 and 3.46 regions and a par t ia l ly resolved CH3t r ip le t at 1 .206, J = 7.0 Hz] are present .

Coordination compounds derived from transition metal salts and bis(3,5-dimethylpyrazolyl)methane

Abstract: The preparation of transition metal complexes containing the sterically hindered ligand, bis(3,5-dimethylpyrazolyl)methane (LL) is described. Compounds of formula M(LL)X2 (M = CoII, NiII or ZnII and X = Cl− or Br−) or M(LL)2X2 (M = MnII, FeII, CoII, NiII, CuII, ZnII or CdII and X = ClO4−; M = CoII, NiII, CuII or ZnII and X = NO3−; M = NiII or CuII and X = Cl− or Br−) have been isolated. In addition, an apparently trimeric Cu3(LL)4Cl6 · EtOH compound is reported. For Ni(LL)Cl2 a five-coordinated chloro-bridged dimer is found. The perchlorato compounds, M(LL)2(ClO4)2, appear to have one bidentate ClO4− and one ionic ClO4− group. The M(LL)2 species appears to occur either in octahedral geometry, leaving twocis-positions free, or in a tetrahedral geometry without space for other ligands, and probably also in a five-coordinate geometry with one free ligand position.

The synthesis and ligand properties of the dihydro-bis-(1-indazolyl)borate anion

Abstract: Potassium dihydro-bis-(1-indazolyl)borate, synthesized from potassium borohydride and indazole, has been used as a reagent to yield complexes with copper(II), nickel(II), cobalt(II), manganese(II) and iron(III) ions. From i.r. spectral studies the ligand is uninegative and bidentate and coordination occurs through the nitrogen atom at position 2 of the indazole ring system in all cases. With the sole exception of the copper(II) complex, the nitrogen atom at position 1 is also involved in forming a bridge with an adjacent metal ion. On the basis of electronic spectral studies and magnetic susceptibility measurements a distorted square planar structure involving chlorine bridges has been proposed for the copper complex. An octahedral geometry with ligand bridges for all complexes is tentatively proposed and it appears that all are polymers.

Copper(ii) complexes of sulfanilamide derivates

Abstract: Nine different CuII(sulf)2 and three mixed CuII(sulf)2X2–3 (X=NH3 or pyridine) derivatives were prepared from CuII and sulfanilamides (sulfH=sulfadiazine, sulfadimethoxine, sulfadimidine, sulfamerazine, sulfamethoxydiazine, sulfamethoxypyridazine, sulfapyridine, sulfathiazole and sulfisomidine) in alkaline solution and their e.s.r., i.r. and ligandfield spectroscopic properties were evaluated. Two types of Cu(sulf)2 complexes were formed: dimeric and monomeric/ polymeric species.

Molecular structures and solid-solid phase transitions of trinuclear CpCo[P(O)(OR)2]32M complexes

Abstract: The trinuclear complexes {CpCo[P(O)(OMe)2]3}2Co and {CpCo[P(O)(OEt)2]3}2M, where M=Mg, Ca, Sr, Ba, Pb, Mn, Co, Ni, Cu, Zn, Cd or Hg, have been studied by x-ray diffraction methods and the crystal structures of {CpCo[P(O)(OR)2]3}2M [R=Me with M=Co (1) and R = Et with M = Cu (2)] have been solved by the heavy atom technique. Complex (2) crystallizes in the triclinic space group P 1 with two crystallographically independent molecules per unit cell. The cell dimensions area = 12.195(3) A,b = 20.429(6) A, c = 12.518(3) A,α = 102.39(2)°, β=120.15(2)°, γ=92.28(2)°. The molecule contains two cobalt atoms and one copper atom in a linear arrangement with copper situated on a center of symmetry. Each of the cobalt atoms is bonded to a cyclopentadienyl ring and is connected to the central copper atom by three phosphonate groups acting as bridging ligands. Disorder phenomena within these phosphonate groups are best described as an enhanced thermal motion corresponding mainly to a rotation around the Co-Cu-Co axis. The CuO6 coordination octahedra exhibit a small (4+2) distortion.

Azido- and phosphiniminato-complexes of titanium and vanadium

Abstract: The azido complexes [Ti(η5-C5H5Cl2(N3)], [Ti(η5-C5H5)2Cl(N3)], [TiCl(N3)(S2CNEt2)2] and [Ti(N3)(S2CNEt2)3] have been prepared from appropriate metal halides by reaction with trimethylsilylazide. The [Ti(η5-C5H5)Cl2(N3)] complex reacts with HC1 and MeCOCl to give HN3 and MeNCO respectively and [Ti(η5-C5H5)Cl3], whereas [Ti(η5-C5H5)Cl2(NPPh3)] is formed on reaction with PPh3. The phosphiniminato complexes [TiCl(NPPh3)(S2CNEt2)2], [TiCl2(NPPh3)2], [VOCl2(NPPh3)], [VOCl(NPPh3)2] and [VCl3(NPPh3)2] have been prepared from the appropriate halido-complexes and Me3SiN=PPh3.

The molecular structure of tetracarbonylhydrido(1,1,4,4-tetraphenyl-1,4-diphosphabutane)vanadium(+I), HV(CO)4(Ph2PCH2CH2PPh2)

Abstract: The crystal and molecular structures of the title compound have been determined The compound crystallizes in the orthorhombic space group Pcab witha = 14633(30),b = 16631(36),c = 22501(47) pm and Z = 8 The molecular structure is best described as a distorted pentagonal bipyramid, the hydride ligand lying in a plane formed by vanadium, the two phosphorus atoms and two carbon monoxide groups The V-H bond length is 1552(93) pm, and the distance between H− and the nearest phosphorus atom is 1579(118) pm In solution, HV(CO)4Ph2P(CH2)2PPh2 appears to be fluxional

Coordination compounds of hydrazine derivatives with transition metals, part XVIII. Cobalt(II) and cobalt(III) chelates with schiff bases derived from hydrazine-S-methyldithiocarboxylate and thiosemicarbazide

Abstract: The reactions of aldehydic and ketonic Schiff bases derived from hydrazine-S-methyl dithiocarboxylate and thiosemicar-bazide with cobalt(II) acetate were investigated. Octahedral tris ligand cobalt(III) chelates were formed with aldehydic Schiff bases whereas tetrahedral bis ligand cobalt (II) chelates were isolated with ketonic Schiff bases.N-isopropylidene hydrazine-S-methyldithiocarboxylate, however, gave both octahedral tris cobalt(III) and tetrahedral bis cobalt(II) chelates. These results are interpreted in terms of the steric requirements of the Schiff base used.

Coordination compounds of hydrazine derivatives with transition metals, Part 17. Nickel (II) and cobalt(II) chelates with pyridine-2-aldehyde semi- and thiosemicarbazone

Abstract: The chelation abilities of both pyridine-2-aldehyde semicarbazone (Pysc) and thiosemicarbazone (Pytsc) towards NiII and CoII salts have been investigated. A series of pentacoordinate monoligand chelates: Ni(Pysc)X2, Ni(Pytsc)X2 and Co(Pysc)X2 and octahedral bis ligand chelates Ni(Pysc)2X · NO3 Ni(Pytsc)2X2 and Co(Pysc)2X2 have been isolated and identified. In these chelates, both Pysc and Pytsc act as neutral tridentate ligands. The deprotonated form of Pyts, which arises through enolization, is identified in NII chelates and is of the type Ni(PytscH)2 and Ni(PytscH)X. Spectral and magnetic measurements are presented and attention is drawn to the effect of temperature on the solution spectra of some of the chelates.

Crystal structure of tris(2-pyridylthio-2-pyridinium)pentaisothiocyanato-dioxouranate(VI)

Abstract: The crystal structure of [DPSH] 3 + [UO2[NCS)5]3− (DPSH = 2 pyridylthio-2-pyridinium) has been determined by standard methods using diffractometer data Crystals are monoclinic, space groupP21/a, witha=3316 (3),b=1668(2),c=785(1) A, andβ=973(1)∘; Dc=165 g · cm−3 for Z=4 The structure has been refined to R=58% by least squares methods Five thiocyanate groups are equatorially bonded to the linear uranyl group The mean of the five U-N, N-C, and C-S bond distances are 245, 117, and 159 A respectively The protonated DPS molecules have the N,N-inside conformations

The crystal and molecular structure of diaquadichlorotheophyllinecopper(II)

Abstract: The crystal structure of CuCl2(C7H8N4O2)(H2O)2 has been determined from diffractometer data by Patterson and Fourier methods and refined by full-matrix least-squares to R=0.067 for 2123 observed reflections. Unit cell constants are:a=9.930(8),b=9.987(8),c=7.483(6) A,α=123.2(1),β=94.5(1),γ= 83.9(1)°. The space group is P¯1 withZ=2. The structure consists of diaquadichlorotheophyllinecopper(II) complexes linked by hydrogen bonds. The coordination polyhedron of copper is a square pyramid whose base, severely tetrahedrally distorted, is formed by a water molecule [Cu-Ow=2.025(7) A], two chlorines [Cu-Cl=2.273(4), 2.296(4) A] and an imidazole nitrogen [Cu-N=1.983(9) A] from the theophylline ligand. A second water molecule is at the apex of the pyramid [Cu-Ow=2.292(7) A]. Coordination is completed to a distorted octahedral one by a long Cu ... O=3.164(7) A contact involving the exocyclic oxygen at C6 of the theophylline ligand.

The behaviour of the AsCo3(CO)9 cluster as a ligand for Cr, Mo, W, and Fe carbonyls and AlCl3

Abstract: The n-donor character of the AsCo3(CO)9 cluster has been tested by reacting it with soft (metal carbonyls) and hard (AlCl3) Lewis acids. The (CO)xM→AsCo3(CO)9 compounds (with M=Cr, Mo or W, x=5; M=Fe, x=4) and Cl3Al → AsCo3(CO)9 have been prepared.

Polyferrocenylenes by oxidative coupling of 1,1′-dilithioferrocene with Cu 2+ Ion (1)

Abstract: The oxidative coupling of 1,1 ′-dilithioferrocene (chelated withN,N,N′,N′-tetramethylethylenediamine) in the presence of CuII halide (Cu2+∶Li=1−1.5) in ether solvents at −70 to 110° gives 30–45% yields of polyferrocenylene. Still higher yields of coupling products result from reactions in which oxidative coupling is paired with thermal coupling,i. e. C-C bond formation through thermal decomposition of organocopper(I) intermediates in the absence of external oxidant (Cu2+∶Li=0.5). Number-average molecular masses of the highest fractions of linear products (2) as separated in the primary work-up process are in the 1500–3400 range, and fractionating precipitation results in subfractions with Mn as high as 5000. Cyclization of dinuclear intermediates, producting up to 10% of [0,0] ferrocenophane (bisfulvalenediiron), competes in all experiments with linear propagation. Experiments conducted with CuI halides under conditions leading exclusively to thermal coupling provide even higher conversion to the ferrocenophane (up to 25% yields) at the expense of linear condensation products. Spectroscopic features of the polyferrocenylenes are discussed. In the linear compounds with ¯Mn>800, i.r. absorptions and p.m.r.'s are remarkably invariant with the degree of polymerization, as are the electronic absorption maxima. This shows, in confirmation of earlier reports, that there is insignificant resonance interaction between the cyclopentadienyl rings in the ferrocene system and hence little, if any, electronic delocalization along the polymer chain of heteroannularly interlinked polyferrocenylene structures.

Synthesis of poly-1,1′-ferrocenylenesvia ferrocenylenecuprates(1)

Abstract: The solution polycondensation of TMEDA-chelated 1,1′-dilithioferrocene in the presence of Cu+ ion, leading to polyferrocenylenes, is explored, the cupration stoichiometry (Cu∶Li=ca. 0.5) being such as to favor the intermediacy of ferrocenylenecuprates, R2CuLi (R=0.5 ferrocenylene unit). In the first series of experiments, the cuprate intermediates are allowed to undergo thermal or oxidative poly-coupling; in subsequent experiments, they are copolymerized with 1,1′-diiodoferrocene. Both reaction sequences result in the formation of linear oligomeric and polymeric coupling products essentially identical in composition and spectroscopic properties with the poly-1,1′-ferrocenylenes of previous investigations. Best results are obtained in the copolymerizations with the diiodo derivative, which give higher overall yields (70–75%) and molecular masses (typically 4000 for the first fraction) than attained in earlier work. In addition, whereas previous syntheses involving either the oxidative coupling of the dilithioferrocene with Cu2+ ion or the oxidative-thermal coupling of ferroceny-lenecopper(I) intermediates gave large quantities of the dinuclear [0.0]-ferrocenophane at the expense of linear polyferrocenylenes, the copolymerizations with diiodoferrocene distinctly favor linear propagation, and yields of the ferrocenophane are less than one percent. The organocuprate/organoiodide coupling reaction thus constitutes a preparative approach to polyferrocenylenes superior to previous syntheses described.

Mineral formation from aqueous solution, part II. The stability of langite, Cu4So4(OH)6 · H2O

Abstract: Naturally occurring waters in the vicinity of complex Cu orebodies have been collected where they are responsible for the precipitation of solid langite, Cu4SO4(OH)6 · H2O, and malachite, Cu2CO3(OH)2. The solutions were analysed and from computer fitting of results the solubility product of langite has been calculated as log Ksp=−17.3 (0.2). This value has enabled the stability field of langite to be estimated and the relationship of this compound to other basic cupric sulphates is discussed.

Structural researches on metal complexes with ligands containing the pyridoxal moiety: X-ray structure of chloro(N-pyridoxylidene-N′-salicyloylhydrazinato) copper(II) Monohydrate

Abstract: The x-ray crystal structure of the title complex is described Crystals are monoclinic, space groupP21/n, with unit-cell dimensions:a=18.070(2),b=13.471(2),c=6.788(2) A,β=94.70(1)∘,Z=4. The structure was solved from diffractometer data by Patterson and Fourier methods and refined by least-squares techniques toR=5.0% for 2451 independent reflections. It consists of complex molecules, in which the copper atom square planar coordination comprises the chlorine atom, Cu-Cl=2.240(3) A, and the organic ligand which acts as terdentate through the oxygen atom [Cu-O=1.948(3) A] and a nitrogen atom, [Cu-N=1.933(5) A] from the hydrazidic chain and the oxygen atom, [Cu-O = 1.894(4) A] from the pyridoxal group.

Equilibria in complexes ofN-heterocyclic molecules, part XXII. The reaction of triaquo(2,4,6-tri-(2-pyridyl)-1,3,5-triazine) copper(II) and its nickel(II) and cobalt(II) analogues with water and hydroxide ion

Abstract: The kinetics of the reaction of [Cu(TPT)(H2O)3]2+ and [Ni(TPT)(H2O)3]2+ with H2O have been followed and it has been shown that the formation of covalent hydrates is important in the understanding of these systems. The [Co(TPT)(OH)3]− compound and its Ni analogue are attacked by HO− initially to form pseudo-base species and in, the case of Ni , the ligand then hydrolyses to yield a compound related to the carboximate formed when HO− reacts with [Cu(TPT)(OH)3]−. In this reaction too, the formation of a pseudo-base, involving attack of HO− at the triazine ring in the ligand is significant.